Fabrication of integrated circuit devices, such as memory devices, microprocessors, and the like, commonly involves the use of chemical mechanical polishing (CMP) to remove materials from a wafer surface and/or to planarize the surface of the wafer before building up additional structures. Generally, CMP involves rubbing the surface of the wafer against a polishing pad made of a resilient material, such as polyurethane, in the presence of a chemical slurry to remove material, such as a metallization layer, deposited on the wafer surface.
Several different types of CMP machines have been developed. One type of CMP machine uses a disk-shaped polishing pad that is affixed to a fixed or rotating polisher. An example of such a machine is illustrated in FIG. 1. As illustrated, the machine includes a polishing pad 12 affixed to a polisher 10 and a wafer 22 supported by a carrier 20. The carrier 20 typically rotates the wafer 22 and presses the rotating wafer's surface against the polishing pad 12. The polisher 10 may or may not rotate. A slurry 41 may be supplied between a wafer 22 and the polishing pad 12 from an external slurry supply device 40. The slurry 41 functions as a chemical polishing abrasive for use in the CMP process. The slurry 41 may be supplied from the external slurry supply device 40 through a supply nozzle 60 while the wafer 22 is pressed and rotated on the polishing pad 12. Generally, the supply nozzle 60 extends to a central portion of the polishing pad 12 and slurry 41 is pumped through the supply nozzle using the pump 42.
Furthermore, chemicals 31 and deionized water 51 may also be supplied to the polishing pad 12 by an external chemical supply device 30 and the external deionized water supply device 50, respectively, through the supply nozzle 60 using first and second pumps 32 and 52, respectively. The slurry 41, chemicals 31 and deionized water 51 may be mixed at a certain point and supplied to the polishing pad 12. The polishing pad 12 may include grooves and the mixture of slurry 41, chemicals 31 and deionized water 51 may be provided in the grooves of the polishing pad 12. Accordingly, the mixture of the slurry 41, chemicals 31 and deionized water 51 may be used to polish the wafer 22 as the wafer is pressed and rotated on the surface of polishing pad 12 during the CMP process.
As discussed above, the polishing pad 12 may have surface features, such as grooves, that can aid distribution of slurry across the surface of the wafer, as shown in, for example, U.S. Pat. No. 6,561,873 to Tsai et al. CMP machines that impress a spinning wafer against a belt-type polishing pad, as shown, for example, in U.S. Pat. No. 6,634,936 to Jensen et al. and U.S. Pat. No. 6,585,579 to Jensen et al.
Conventional polishing devices, for example, device 90 of FIG. 1, use external supply devices 30, 40 and 50 for supplying one or more of chemicals 31, a slurry 41 and deionized water 51. The presence of these additional devices may require more space to operate the polishing device so that a CMP process can be performed. Furthermore, some conventional polishing devices receive the slurry through a first supply line and the chemicals through a second supply line. Providing the slurry and the chemicals through different supply lines may add an additional level of difficulty, as process conditions may vary depending on a mix ratio of slurry and chemicals.